good to know rettepnoj. I too use a Bach 3C. Purchased a Stork custom Vacchiano 3C a while back and am now going to give it some time to see if I find the improvement you were so fortunate to have. Continued good luck, and Happy New Year.

There are many factors to consider in mouthpiece cups, seemingly as many as the appearance of individuals IMO.
First, the overall width. Second the width of the rim itself. Third, the shape of the rim, vis flat or crowned. Next, we consider the cup internal curvature and depth, and lastly the throat size.

The final summation is what is favored by one person may not be by another and to some extent this is justified by the differences in their individual physiology. I've played so many that pass through my hands that I no longer keep track of them and mostly seem to "make do" with whatever even though I discern some seem more difficult to work with certain instruments than with others.

I won't stick my neck out and suggest any. Too, I won't tell you what I prefer to play even though I know of very few others that play what I play. It's just coincidental that I often play a mouthpiece of the type once played by a very renown trumpet player.

Mouthpiece selection is a well known "safari", but I can tell you to seek out what is comfortable for you and allows you to produce the sound you expect or want to hear.

Dale, having perused Dr. Hall's treatise on cup mouthpieces, I conclude that other than engineering aspects when one "cuts to the chase" it adds nothing to an individual musician's preference of mouthpiece, just as the Doctor summarizes and illustrates in "Areas of Disagreement".

Too, in contrast to all the other drawings, I can't surmise how the wrap of the "instrument" in Figure 2 would play. It certainly wouldn't comparatively illustrate any brass musical instrument I have, not even a viable bugle.

I play both, and switch between them basically for the quality of sound I am getting from the horn. On my flugelhorn, I love the deep V cup that lets me work on puffs of air within the mouthpiece. This adds so much texture to the sound. But when I am playing lead, the shallow cup gets an instant response for accuracy and crisp presentation when up in the lead range of play.

I see it much like golf... You use a wood to drive, an iron to arch for precision shots, a wedge to get me out of the rough, and the putter to drop it in the pocket.